96 850 Fluctuating idle/stalling (VVIS?)

454cid · Post by **454cid** » 16 Jun 2022, 12:28

How about getting live data on some of those sensors..... TPS would be good to know.

cheap850 · Post by **cheap850** » 16 Jun 2022, 14:15

454cid wrote: 16 Jun 2022, 12:28 How about getting live data on some of those sensors..... TPS would be good to know.

I measured the resistance on the (disconnected) TPS as noted in my earlier post. After some research it seems good, it matches up with the values others have posted. There's no drop anywhere on the rotation either.

O2 sensor (OEM) should arrive saturday, if it doesnt solve the issue I'll just return it :-)

cheap850 · Post by **cheap850** » 16 Jun 2022, 14:47

misha wrote: 16 Jun 2022, 11:40
abscate wrote: 16 Jun 2022, 04:35 VVIS on a 1996? We didn’t get that system over here in that year. Could your engine have been swapped?
It seems that engine has been swapped.

No VVIS on a EU market from '96.

According to this wikipedia page, this might acually be the original B5254S engine, equipped with V-VIS and available on the 850 through 1995-1996. I'll check the sticker this weekend.

https://en.m.wikipedia.org/wiki/Volvo_M ... ine#B5254S

Post by **misha** » 16 Jun 2022, 16:40

I recently read a brochure for 850,online,made for Dutch market only.
It might be it.

Something like 2.0 T5 R made for Italian market only.

One thing is for sure...i have never seen or came across a '96 with VVIS and LH 3.2 Jetronic management.
'92-'95 yes....but no '96.

454cid · Post by **454cid** » 17 Jun 2022, 02:13

cheap850 wrote: 16 Jun 2022, 14:15
454cid wrote: 16 Jun 2022, 12:28 How about getting live data on some of those sensors..... TPS would be good to know.
I measured the resistance on the (disconnected) TPS as noted in my earlier post. After some research it seems good, it matches up with the values others have posted. There's no drop anywhere on the rotation either.

I had troubles trying to do that. I couldn't seem to keep the probes on the connectors reliably enough, but it didn't matter. I already had it replaced, as I had used the 850 OBD2 app to graph the voltage of the TPS, and saw the voltage spike to 5 volts a couple of times, which did not correspond to me opening the throttle. I also took a look at the o2 sensor voltages, and found those to be off.

O2 sensor (OEM) should arrive saturday, if it doesnt solve the issue I'll just return it

Most places won't take back electrical parts, especially if connected.

cheap850 · Post by **cheap850** » 17 Jun 2022, 09:57

misha wrote: 16 Jun 2022, 16:40 I recently read a brochure for 850,online,made for Dutch market only.
It might be it.

Something like 2.0 T5 R made for Italian market only.

One thing is for sure...i have never seen or came across a '96 with VVIS and LH 3.2 Jetronic management.
'92-'95 yes....but no '96.

I can confirm it is indeed the B5254S

cheap850 · Post by **cheap850** » 18 Jun 2022, 03:42

For whoever is reading this troubleshooting their own idle issues: if it runs just as bad with or without the O2 connected, its probably your O2 (lambda) sensor. My problem has been resolved with a new Bosch unit.

Still has some slight idle issues but it actually runs now, I suspect my MAF is also part of the problem.

Everyone thanks for your suggestions!

454cid · Post by **454cid** » 18 Jun 2022, 03:57

cheap850 wrote: 18 Jun 2022, 03:42 For whoever is reading this troubleshooting their own idle issues: if it runs just as bad with or without the O2 connected, its probably your O2 (lambda) sensor. My problem has been resolved with a new Bosch unit.

Still has some slight idle issues but it actually runs now, I suspect my MAF is also part of the problem.

Everyone thanks for your suggestions!

It would be interesting to know what your old O2 was reporting. Mine had been reading very low, so the computer was over fueling the engine trying to compensate for a false lean condition.

cheap850 · Post by **cheap850** » 18 Jun 2022, 05:06

454cid wrote: 18 Jun 2022, 03:57 It would be interesting to know what your old O2 was reporting. Mine had been reading very low, so the computer was over fueling the engine trying to compensate for a false lean condition.

I havent been able to pull live data, but I suspect it was the same issue as it did make the engine run very rich.